log.dart

// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/// Message logging.
library pub.log;

import 'dart:async';
import 'dart:convert';
import 'dart:io';

import 'package:args/command_runner.dart';
import 'package:path/path.dart' as p;
import 'package:source_span/source_span.dart';
import 'package:stack_trace/stack_trace.dart';

import 'exceptions.dart';
import 'io.dart';
import 'progress.dart';
import 'transcript.dart';
import 'utils.dart';

/// The singleton instance so that we can have a nice api like:
///
///     log.json.error(...);
final json = new _JsonLogger();

/// The current logging verbosity.
Verbosity verbosity = Verbosity.NORMAL;

/// Whether or not to log entries with prejudice.
bool withPrejudice = false;

/// In cases where there's a ton of log spew, make sure we don't eat infinite
/// memory.
///
/// This can occur when the backtracking solver stumbles into a pathological
/// dependency graph. It generally will find a solution, but it may log
/// thousands and thousands of entries to get there.
const _MAX_TRANSCRIPT = 10000;

/// The list of recorded log messages. Will only be recorded if
/// [recordTranscript()] is called.
Transcript<Entry> _transcript;

/// The currently-animated progress indicator, if any.
///
/// This will also be in [_progresses].
Progress _animatedProgress;

_Collapser _collapser;

final _cyan = getSpecial('\u001b[36m');
final _green = getSpecial('\u001b[32m');
final _magenta = getSpecial('\u001b[35m');
final _red = getSpecial('\u001b[31m');
final _yellow = getSpecial('\u001b[33m');
final _gray = getSpecial('\u001b[1;30m');
final _none = getSpecial('\u001b[0m');
final _noColor = getSpecial('\u001b[39m');
final _bold = getSpecial('\u001b[1m');

/// An enum type for defining the different logging levels a given message can
/// be associated with.
///
/// By default, [ERROR] and [WARNING] messages are printed to sterr. [MESSAGE]
/// messages are printed to stdout, and others are ignored.
class Level {
  /// An error occurred and an operation could not be completed.
  ///